Main article: Email spam
Spam sent by email is usually meant when it is mentioned outside a specific context. Email has more possibilities for exploitation than other media, since the whole message is compiled along with metadata by the sender's computer. The majority of modern email services attempt to filter incoming messages and identify spam. Instant messaging
Main article: Messaging spam
Instant messaging spam makes use of instant messaging systems. Although less ubiquitous than its e-mail counterpart, according to a report from Ferris Research, 500 million spam IMs were sent in 2003, twice the level of 2002. As instant messaging tends to not be blocked by firewalls, it is an especially useful channel for spammers. This is very common on many instant messaging systems such as Skype. Newsgroup and forum
Main article: Newsgroup spam
Newsgroup spam's a type of spam where the targets are Usenet newsgroups. Spamming of Usenet newsgroups actually pre-dates e-mail spam. Usenet convention defines spamming as excessive multiple posting, that is, the repeated posting of a message (or substantially similar messages). The prevalence of Usenet spam led to the development of the Breidbart Index as an objective measure of a message's "spamminess". Main article: Forum spam
Forum spam is the creating of messages that are advertisements on Internet forums. It is generally done by automated spambots. Most forum spam consists of links to external sites, with the dual goals of increasing search engine visibility in highly competitive areas such as weight loss, pharmaceuticals, gambling, pornography, real estat...